Hydraulic brake system coupler



June 15, 1937. J. w. CARROLL HYDRAULIC BRAKE SYSTEM COUFLER Filed Oct. 4, 1953 mw@ u u (fo/70 M @a Patented June 15, 1937I UNITED STATES PATENT OFFICE nYDRAULro BRAKE SYSTEM coUrLEn John W. Carroll, Detroit, Mich. Application oetober 4, 1933, serial No. 692,193

4 claims. (ci. 18s- 3) The present invention pertains to couplers for connecting hydraulic brake systems and is particularly adapted for use in tractor trailer combinations and with tractors and semi-trailers wherein the braking pressure is applied by means on the tractor and is transmitted through nuid to the trailer or semi-trailer to actuate brakes thereon.

The primary object of the present invention is to provide coupling means for connecting separate hydraulic brake systems so that application of pressure on the fluid in one system tending to actuate the brakes therein, also causes actuation of the brakes forming a part of the other system.

Such a construction is desirable in connection with tractors having a hydraulic brake system and hydraulic pressure means for actuating the brakes thereof so that a trailer or a semi-trailer connected to the tractor may be provided with a hydraulic brake system which may be coupled to the brake system of the tractor to be actuated by the same pressure means and in unison with the brakes on the tractor.

Another object of the present invention is to provide coupling means between a hydraulic brake system on a tractor and a hydraulicwbrake system on a trailer so that a single hydraulic pressure means may be provided to actuate both systems, said coupler being constructed so that uncoupling of the two brake systems does not render the system on the tractor inoperativeand does not occasion loss of uid therefrom.

Another object of the present invention is to provide a coupler for hydraulic brake systems on tractor trailer combinations which provides for actuation of the`trailer brakes" by pressure generating means on the tractor, which coupler provides means Afor disconnecting the brake system on the trailer from the pressure means on the tractor when the tractor is uncoupled from the trailer.'

Another object of the present invention is to provide a coupler between a trailer hydraulic brake system and hydraulic pressure means on a tractor so that when said coupler is disconnected, when the tractor and trailer are uncoupled,`

the brakes on the trailer may be held in an applied position. Such a feature is desirable in order that the tractor and trailer may be easily recoupled.

With the above and other ends in view the invention consists in matters hereinafter set forth and more particularly pointed out in the appended claims, reference being had to the accompanying drawing, in which Figure 1 is a diagrammatic plan of coupled tractor and trailer brake systems;

Fig. 2 is a longitudinal cross section illustrating the parts of the coupler in connected rela tion; and

Figs. 3 and 4 are cross sections of the parts ,of the coupler in separated relation.

Like characters of reference are employed throughout to designate corresponding parts.

With reference to Fig. 1 the numeral l desig-` nates the front wheels of atractor and 2 the rear wheels. Associated with the wheels I and 2 are brakes 3 and 4 respectively and it is to be understood that the brakes include hydraulic mechanisms adapted to be actuated by uid under pressure. The construction of the hydraulic mechanism forms no novel part of the present invention and in View of the fact that numerous types of hydraulic brakes are well known and readily available in the art the same have not been shown in detail. Mounted on the tractor, in a manner also well known in the art, is a cylinder 5 in which is mounted a slidable piston 6 which is adapted to be reciprocated by a foot pedal 1. A line 8 is connected to the cylinder 5 and to each of the brakes 3 and 4. The cylinder 5 and line 8 are iilled with a liquid upon which pressure is applied by movement of the piston 6 as a result o f depressionl of the foot pedal 1.

From the foregoing it will be understood that the tractor and the hydraulic brake system thereon are of conventional constructions and that the same are well known to those versed in hydraulic brake art.

Also diagrammatically illustrated in Fig. 1 are trailer wheels 9 having hydraulic brakes I0 connected together by a line II. It will be understood that the line II is normally full of liquid upon which pressure may be applied in a manner to be presently described in order to actuate the brakes IU.

A coupler cylinderv I2 is attached to a stationary part I3 of the tractor frame and is connected by a tube Il to the line 8. A second coupler cylinder I5 has a flexible tube I6 connected at one end thereto and at its other end to the line Il. The construction of the cylinders I2 and I5 and the association of parts therewith forms the essence of the present invention and will now be described in detail.

'Ihe cylinder I2 is formed with a cylindrical chamber I'I and an end flange I8 to which a cover plate I9 is secured by screws 2B, the cover plate having a central opening 2|. The opposite end of the cylinder I2 has an end wall 22 provided with a passage 23 which connects the pipe I4 to the chamber I1. On the inner end of the 5 passage 23 is formed a valve seat 24. Reciprocally mounted in the chamber I1 is a piston 25 and a flexible cup seal 25 is secured to the piston and interposed between the piston 25 and the passage 23. The flexible seal 26 has a domeshaped protuberance 21 adapted to seat upon the valve seat 24 to close the passage 23 for a purpose and in a manner to be hereinafter set forth.

The coupler part I5 is formed with a cylindrical chamber 28 and an end flange 29 having a cover vplate 30 secured thereto by means of screws 3|.

Y'Ihe cover plate 30 has an opening 32 vcentrally located relative to the axis of the cylindrical chamber 28. The end wall 35 of the coupler part I5, which is opposite to the end having the flange 29. has a passage 33 providing communication between the flexible tube I6 and the cylindrical chamber 28 and surrounding the inner end of this passage is a valve seat 34. Reciprocally mounted in the chamber 28 is a. piston 36 carrying a flexible cup seal 31, the latter being interposed between the piston and the passage 33 and having a dome shaped protuberance 38 adapted to engage the valve seat 34.

The coupler parts I2 and I5 are provided with bleeder passages 39 and 40 respectively communicating with the chambers I1 and 28. Bleeder valves 4I and 42 are adapted to close or open the passages 39 and 40 to facilitate removal of any air which might become trapped in the chambers I1 and 28.

From the foregoing it is apparent that the chamber I1 is in fluid communication with the hydraulic pressure medium 5 and the chamber 28 is in fluid communication with the brakes I0. Therefore it is obvious that pressure applied on the fluid by the hydraulic pressure medium 5 results in movement of the piston 25, and that if the piston 36 were caused to move it would exert a pressure on the fluid in the lines II tending to actuate the brakes I0. Accordingly means is provided to cause movement of the piston 36 in unison with the piston 25, and this means comprises a rod 43 which is interposed between the pistons 25 and 36 while the two coupler parts I2 and I5 are held in end to end relation by attaching elements 44 which engage the flanges I8 and 29.

In operation, fluid under pressure created by the pressure medium 5v passes through the tube I4 and passage 23 to enter the chamber I1. I'he fluid under pressure expands the seal 26 to prevent possibility of any leakage and also causes longitudinal movement of the piston 25 in the right hand direction relative to Fig. 2. 'Ihe rod y 43, which extends through the openings 2| and 32 in the cover plates I9 and 30, is also caused to movelongitudinally to transmit like movement to the piston 44. Movement of the piston 44 in a direction toward the right of Fig. 2 forces the fluid from the chamber 28 to the brakes I0 and causes actuation thereof. Inasmuch as the movement of the piston 25 only happens when the fluid in the lines 8 is under pressure, that movement takes place while the brakes 3 and 4 are being applied and thereforethe brakes 3 and 4 and the brakes I0 will be applied simultaneously by operation of the hydraulic pressure medium 5.

75 In Fig. 3 the coupler member I2 is shown uncoupled from the coupler member I5 and in order to hold the piston 25 against movement when the hydraulic pressure medium 5 is actuated there is provided a cap 45 which is secured to the flange I8 by bolts 44 which were previously employed to secure the flange .29 thereto. The cap 45 engages the end of the rod 43 so that when the bolts 44 are tightened the piston 25 is held in a position where the protuberance 21 engages the Valve seat 24 to close the passage 23. Thus there is no possibility of fluid under pressure entering the chamber II to escape from the hydraulic brake system on the tractor, or in a manner to build up pressure on the piston 25 tending to move the same.

If it is` desired to hold the trailer brakes in their set position after the coupler parts I2 and I5 have been uncoupled a cap 46 is secured to the flange 29 by bolts 41, or other known securing means. In the cap 46 is mounted a screw-threaded rod 48 which is adapted to` engage the piston 36 to hold it in any desired position of adjustment or in some cases to force the piston to a position where the dome shaped protube-rance 38 engages the valve seat to prevent 'the fluid in the trailer brake system from entering the chamber 28. For rotating the screw 48 manually there is provided a handle 49.

From the foregoing it becomes apparent that the present coupler provides means for connecting two separate hydraulic brake systems so that both systems may be actuated by a common hydraulic pressure medium. It is also apparent that the piston 25 which, when coupled, moves as a result of brake actuating pressure on the tractor, does not move as a result of such pressure when the coupler is not uncoupled, and accordingly does not reduce the efficiency of the tractor brakes nor does it permit leakage of fluid. Furthermore, it becomes apparent that the piston 44 may be held in a position where the fluid is trapped in the trailer brake .system with the brakes of said system in their set position, or the piston may be permitted to move freely in order that no pressure tending to apply the trailer brakes is built up thereby.

Although a specific embodiment of the present invention has been illustrated and described it is to be understood that various changes may be made within the scope of the appended claims Without departing from the spirit of the invention, and such changes are contemplated.

What I claim isz- 1. The combination with two separate hydraulic brake systems, of a fluid pressure medium in one of said systems, a pair of coupling elements each in fluid communication with one of said systems, movable elements in said coupling elements, and means in at least one of said coupler elements rendered operative by movement of the movable element therein for sealing the said coupler element against fluid communication with its connected system.

2. A device for connecting two independent fluid pressure brake systems so that pressure on the fluid in one system is transmitted to the fluid in the other system, said device comprising two cylindrical bodies each having one of their ends closed by walls provided with means for connecting them to respective brake systems, a piston mounted in each of said cylindrical bodies, means carried by at least one of said pistons for sealing the means for providing communication of its respective cylindrical body with its respective brake system, plates removably mounted on the other ends of said cylindrical bodies, said plates having central apertures therein, a rigid element extending throughthe said apertures and having its opposite ends engaging pistons in different bodies, and means for detachably securing said cylindrical bodies together.

3. A device for connecting two independent iiuid pressure brake systems so that pressure on the uid in one system is transmitted to theflui/d in the other system, said device.comprisingim'loy cylindrical bodies each having one of their ends closed by walls provided with means for connecting them to respective brake systems, a piston mounted in each of said cylindrical bodies, plates removably mounted on the other ends of said cylindrical bodies, said plates having centrally disposed centering apertures therein, a rigid element extending through the centering apertures and having its opposite ends loosely engaging pistons in different bodies, and means for detachably securing said cylindrical bodies together.

4. A device for connecting two independent fluid pressure brake systems so that pressure on the fluid in one system is transmitted to the uid in the other system, said device comprising two cylindrical bodies each having one of their ends closed by walls provided with means for connecting them to respective brake systems, a piston mounted in each of said cylindrical bodies, plates removably mounted on the other ends of said cylindrical bodies, said plates having centrally disposed centering apertures therein, a rigid element loosely inserted through the centeringA apertures in said plates and having its opposite ends in unsecured engagement with pistons in diierent cylindrical bodies, and detachable means for securing said cylindrical bodies together.

JOHN W. CARROLL. 

